Esophageal squamous cell carcinoma (ESCC) ranks sixth among all cancers worldwide, with 450,000 new cases diagnosed per year and a very poor prognosis. Low-cost, minimally invasive point-of-care population screening for ESCC is badly needed, particularly in LMICs, where 5-year ESCC survival is less than 10%. Altered methylation occurs frequently in human malignancies, including EC, constituting an early event that can serve as an early cancer detection biomarker. However, for DNA methylation to be used in this manner, we need cost-effective, user-friendly and robust tests that permit clinical translation in LMICs. We propose an early ESCC diagnostic strategy comprising a single-use, swallowable sponge to collect esophageal specimens coupled with a smartphone-manipulated microfluidic chip for automated sample processing and methylation detection. This strategy does not require endoscopy (EGD), can be administered by healthcare workers without medical degrees, and uses an on-phone analytic app. The sponge is cheaper (approximately $30 each), less invasive, and easier to perform than EGD ($1500 total cost, including facility fees); there are no room charges, unlike EGD. The microchip integrates DNA extraction, bisulfite DNA conversion, and methylation analysis into a single device. In addition, the microchip interfaces with a cellphone, for both device control and methylation detection and analysis. The integrated device enables detection of DNA methylation from crude samples in a ?sample-to-answer? manner, without the need for sending data back to an analytic center off-site. Thus, the proposed platform promises a cost-effective and user-friendly POC strategy for early ESCC detection that is implementable in LMICs. We have also assembled a talented interdisciplinary, intercontinental team to execute this strategy. Our task will be achieved in 2 phases via the following Aims: UG3 PHASE: Aim 1: To assess a streamlined protocol for sample collection, processing and methylation detection. Aim 2: To implement DNA sample processing and methylation detection into a mobile phone- manipulated microfluidic chip system. Aim 3: To test a prototype ESCC diagnostic strategy integrating the DNA methylation detection system with the swallowable sponge for sample collection. UH3 PHASE: Aim 1: To improve the cost-effectiveness and robustness of the methylation diagnostic system for use in LMICs. Aim 2: To develop a method for ambient chip storage and perform on-chip QC tests to verify assay functionality. Aim 3: To conduct an ESCC diagnostic trial in Uganda using our point-of-care strategy.